What's cooler than being cool? Being almost as cold as physically possible, of course.

In NASA's Cold Atom Laboratory located on the International Space Station, scientists are able to produce clouds of atoms that can reach just a fraction of a degree above absolute zero, thought to be the lowest temperature possible.

The CAL is often the coldest known place in the universe, and for good reason. By having the lab in space, scientists are able to better able to understand atoms and how to use them. The experiments performed in the CAL help scientists to better understand the physical properties of atoms as well as the fundamental laws of physics.

It's necessary to perform such experiments in space because on Earth, although it's possible to produce the "ultracold" atoms the CAL makes, scientists have only a fraction of a second to observe them because the planet's gravity pulls on the cloud. The atoms float much longer in space.

Launched from Wallops Flight Facility in two pieces in May 2018, the Cold Atom Laboratory produces ultracold atoms every day. In its first year, five teams will use it for experiments; three are already underway.

It can be difficult to get atoms to reach such a cold temperature. Scientists start by using lasers to slow them down, as an atom typically zips around quickly, according to a release by NASA's Jet Propulsion Laboratory, which designed and built the CAL.

Radio waves are then used to remove the warmest atoms of the bunch, bringing the temperature down more. The atoms are then released from a magnetic trap and allowed to expand. That makes pressure drop, which makes the temperature drop, according to NASA.

The cloud expands and reaches lower temperatures from there. In space, it can expand for longer and reach lower temperatures than what they'd reach on Earth.

The CAL was designed to be controlled remotely from Earth. It was also structured to withstand launch and the extreme forces things face when launched from the surface of the Earth.

It is the second ultracold atom facility ever operated in space, according to NASA. It is the first, however, to reach orbit, and it was the first to be in space for more than just a few minutes. The Jet Propulsion Lab reported that the lab has met the minimum requirements necessary for NASA to consider the mission a success.